Level shifters are devices that resolve mixed voltage incompatibility between different parts of a system that operate in multiple voltage domains. They are common in today's complex systems, especially when interfacing with older legacy devices. There are a broad variety of standard, general-purpose level-shifters that utilize or provide a wide range of voltages, frequencies, bit widths and IO types (e.g., open-drain or push-pull) in addition to performance-optimized application specific level shifters for standard device interfaces (e.g., I2C, SD card, SIM card).